High demands on both softness and dryness are made on liquid-pervious cover layers for absorbent articles of this type, which are intended to bear on the body of the user during use.
However, it has proved to be difficult to achieve a liquid-pervious cover layer with a soft and textile-like surface which at the same time remains dry during use.
One problem, when using nonwoven materials or other similar textile materials as liquid-pervious cover layers for absorbent articles, is that the fibre structure of the material absorbs liquid when the cover layer is wetted. A certain amount of the liquid is not conducted downwards to the underlying absorbent structure, but remains in the liquid-pervious cover layer instead. Since the liquid-pervious cover layer bears on the body of the user during use, such articles are perceived as being wet and uncomfortable to wear already after an initial wetting.
Furthermore, the wet surface, which is in direct contact with the skin during use, leads to an increased risk of skin irritations and infections.
The most important reason for some of the liquid remaining in the fibre structure is that textile materials usually consist of an irregular fibre structure with fibres or fibre filaments oriented in the plane of the material. This implies that excreted body fluid, by means of the capillary action of the fibres, is distributed along the fibre structure in the direction of the material plane. Also liquid which is not absorbed into the fibre capillaries is conducted along the fibre structure in the direction of the material plane, and is collected in cavities between the fibres in which the liquid is retained without being able to spread further to underlying material. These factors result in a certain amount of liquid remaining in the cover layer and causing a wet surface closest to the user.
Another problem with the nonwoven materials of today, having fibres substantially oriented in parallel with the material plane, is that the possibility to control the wetting course by means of utilizing the properties of the fibres, such as for example the wettability of different fibres, is limited. Furthermore, the possibility to control the wetting course is limited when it comes to the location of the fibres and their design.
It is previously known from U.S. Pat. No. 3,967,623 to use a liquid-pervious cover layer, consisting of a perforated plastic layer, as a carrier material onto which fibres treated with wetting agent are applied in order to create a soft and fluffy surface. The individual fibres are oriented so that they are directed upwards towards the user during use and are approximately 5 mm long. Since the fibres are directed upwards towards the user, a soft and fluffy surface is created. However, the problem remains that the liquid transfer from the fibres to the underlying absorbent body inside is poor, which results in the surface closest to the user remaining wet after wetting.
BE 09300552 relates to a cover layer for an absorbent article, which cover layer consists of a plastic film which at least on one side is covered by fibres which are attached at an angle to the plastic film. In order to obtain such a structure, the fibres may, for example by means of flocking, be attached with one of their fibre ends against a fused fibre fixation layer on the plastic film. The plastic film may be perforated so that the material becomes liquid-pervious. The fibres are 0.3 to 2.5 mm long and the thickness may be varied with regard to how soft the layer should be. Different fibres may be used, such as for example viscose, cotton, polyethylene, polypropylene, polyester and polyamide.
The risk of the liquid spreading in the plane of the material and thereby along the surface of the cover layer is minimal with this previously known cover layer. Furthermore, the cover layer exhibits a soft surface closest to the user. With this previously known cover layer, however, the problem of achieving a dry surface, when the layer is used as a liquid-pervious surface material on an absorbent article, still remains.